P
US6048632AExpiredUtilityPatentIndex 92

Self-biasing, non-magnetic, giant magnetoresistance sensor

Assignee: NEC RESEARCH INSTPriority: Aug 22, 1997Filed: Aug 22, 1997Granted: Apr 11, 2000
Est. expiryAug 22, 2017(expired)· nominal 20-yr term from priority
Inventors:SOLIN STUART ATHIO TINEKEKAWANO MASAYA
G11B 5/33B82Y 25/00Y10T428/1136G01R 33/093G11B 2005/3996B82Y 10/00Y10S428/90Y10T428/115
92
PatentIndex Score
19
Cited by
5
References
32
Claims

Abstract

A self-biasing, non-magnetic giant magnetoresistive sensor having a Corbino-disk geometry constructed from a thin film of e.g., doped, Mercury Cadmium Telluride (MCT) Hg 1-x Cd x Te exhibiting anomalously large Giant Magnetresistance (GMR) and zero field offset. In one embodiment, the sensor has a silicon substrate, a layer of doped, inhomogeneous MCT, and electrodes attached to the inhomogeneous layer. Alternatively, a buffer layer of, e.g., CdTe may overlay the substrate. In another embodiment, the sensor has a silicon substrate, a layer of doped, homogeneous MCT, and electrodes attached to the doped homogeneous MCT. Alternatively, a buffer layer of, e.g., CdTe may overlay the substrate as well. With constructed in as either of these embodiments, highly doped Corbino devices may show a significant zero-field offset in the GMR which results in a built-in bias field as high as 1500 G at T=300 K.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A sensor having a magnetoresistive effect for sensing magnetic patterns, stored as a series of magnetic domains in a storage device, said sensor comprising: a substrate;   a layer of inhomogeneous doped magnetoresistive material, overlying said substrate wherein said magnetoresistive material is sufficiently doped to produce a large zero-field-offset of as much as 1500 G at room temperature within said material; and   a plurality of electrodes, attached to said layer of magnetoresistive material.   
     
     
       2. The magnetoresistive sensor according to claim 1 wherein said layer of magnetoresistive material is doped with an n-type dopant. 
     
     
       3. The magnetoresistive sensor according to claim 2 wherein said n-type dopant within the layer of magnetoresistive material is a Group III element selected from the group consisting of B, Al, Ga, In and Tl. 
     
     
       4. The magnetoresistive sensor according to claim 2 wherein said n-type dopant within the layer of magnetoresistive material is a Group IV element selected from the group consisting of Si, Ge, Sn and Pb. 
     
     
       5. The magnetoresistive sensor according to claim 2 wherein said n-type dopant within the layer of magnetoresistive material is a Group VII element selected from the group consisting of F, Cl, Br, I, and At. 
     
     
       6. The magnetoresistive sensor according to claim 1 wherein said layer of magnetoresistive material is doped with a p-type dopant. 
     
     
       7. The magnetoresistive sensor according to claim 6 wherein said p-type dopant is a Group Ia element selected from the group consisting of Na, K, Rb, Cs, and Fr. 
     
     
       8. The magnetoresistive sensor according to claim 6 wherein said p-type dopant is a Group Ib material selected from the group consisting of Cu, Ag and Au. 
     
     
       9. The magnetoresistive sensor according to claim 6 wherein said p-type dopant is a Group V element selected from the group consisting of N, P, As, Sb and Bi. 
     
     
       10. The magnetoresistive sensor according to claim 1 further comprising a buffer layer interposed between said substrate and said magnetoresistive layer. 
     
     
       11. The magnetoresistive sensor according to claim 10 wherein said buffer layer is substantially Cadmium Telluride. 
     
     
       12. A sensor with a magnetoresistive effect for sensing magnetic patterns, stored as a series of magnetic domains in a storage device, said sensor comprising: a substrate;   an inhomogeneous layer of magnetoresistive material consisting substantially of doped Mercury Cadmium Telluride, Hg 1-x  Cd x  Te, overlying said substrate, wherein said Mercury Cadmium Telluride is sufficiently doped to produce a large zero-field-offset of as high as 1500 G at room temperature within said material; and   a plurality of electrodes, attached to said inhomogeneous layer of magnetoresistive material.   
     
     
       13. The magnetoresistive sensor according to claim 12 wherein said inhomogeneous layer of Mercury Cadmium Telluride is doped with an n-type dopant. 
     
     
       14. The magnetoresistive sensor according to claim 13 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group III element selected from the group consisting of B, Al, Ga, In and Tl. 
     
     
       15. The magnetoresistive sensor according to claim 13 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group IV element selected from the group consisting of Si, Ge, Sn and Pb. 
     
     
       16. The magnetoresistive sensor according to claim 13 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group VII element selected from the group consisting of F, Cl, Br, I, and At. 
     
     
       17. The magnetoresistive sensor according to claim 12 wherein said inhomogeneous layer of Mercury Cadmium Telluride is doped with a p-type dopant. 
     
     
       18. The magnetoresistive sensor according to claim 17 wherein said p-type dopant is a Group Ia element selected from the group consisting of Na, K, Rb, Cs, and Fr. 
     
     
       19. The magnetoresistive sensor according to claim 17 wherein said p-type dopant is a Group Ib material selected from the group consisting of Cu, Ag and Au. 
     
     
       20. The magnetoresistive sensor according to claim 17 wherein said p-type dopant is a Group V element selected from the group consisting of N, P, As, Sb and Bi. 
     
     
       21. The magnetoresistive sensor according to claim 12 further comprising a buffer layer interposed between said substrate and said inhomogeneous magnetoresistive layer. 
     
     
       22. The magnetoresistive sensor according to claim 21 wherein said buffer layer is substantially Cadmium Telluride. 
     
     
       23. A magnetoresistive sensor for sensing magnetic patterns stored as a series of magnetic domains in a storage device comprising: an inhomogeneous semiconductive wafer of magnetoresistive material consisting substantially of doped Mercury Cadmium Telluride having at least one planar surface, wherein said Mercury Cadmium Telluride is sufficiently doped to produce a large zero-field-offset of as high as 1500 G at room temperature within said material;   electrode means including an inner electrode and an outer electrode surrounding the inner electrode on the planar surface of the inhomogeneous semiconductive material; and   means for supporting the planar surface of the inhomogeneous semiconductive wafer of magnetoresistive material adjacent to the magnetic patterns stored on the storage device.   
     
     
       24. The magnetoresistive sensor according to claim 23 further comprising: buffer means positioned between said supporting means and said inhomogeneous semiconductor wafer.   
     
     
       25. The magnetoresistive sensor according to claim 23 wherein said inhomogeneous layer of Mercury Cadmium Telluride is doped with an n-type dopant. 
     
     
       26. The magnetoresistive sensor according to claim 25 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group III element selected from the group consisting of B, Al, Ga, In and Tl. 
     
     
       27. The magnetoresistive sensor according to claim 25 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group IV element selected from the group consisting of Si, Ge, Sn and Pb. 
     
     
       28. The magnetoresistive sensor according to claim 25 wherein said n-type dopant within the inhomogeneous layer of Mercury Cadmium Telluride is a Group VII element selected from the group consisting of F, Cl, Br, I, and At. 
     
     
       29. The magnetoresistive sensor according to claim 23 wherein said inhomogeneous layer of Mercury Cadmium Telluride is doped with a p-type dopant. 
     
     
       30. The magnetoresistive sensor according to claim 29 wherein said p-type dopant is a Group Ia element selected from the group consisting of Na, K, Rb, Cs, and Fr. 
     
     
       31. The magnetoresistive sensor according to claim 29 wherein said p-type dopant is a Group Ib material selected from the group consisting of Cu, Ag and Au. 
     
     
       32. The magnetoresistive sensor according to claim 29 wherein said p-type dopant is a Group V element selected from the group consisting of N, P, As, Sb and Bi.

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